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E: Executive Summary
Table of Contents
EXECUTIVE SUMMARY ..................................................................................................................................................... 1
E.1 Background ......................................................................................................................................................... 1
E.2 Auckland Stormwater NDC.................................................................................................................................. 2
E.3 Activities for Which Resource Consent is Sought ................................................................................................ 2
E.4 Auckland Stormwater NDC Aims ......................................................................................................................... 3
E.5 Key Stormwater Management Issues ................................................................................................................. 3
E.6 Effects of Diversions and Discharges from the Stormwater Network ................................................................. 5 E.6.1 Stormwater Assets ................................................................................................................................... 5 E.6.2 Effects of Growth ..................................................................................................................................... 5 E.6.3 Flooding ................................................................................................................................................... 6 E.6.4 Effects on Stream Health ......................................................................................................................... 6 E.6.5 Effects on coastal health .......................................................................................................................... 6 E.6.6 Effects on Groundwater ........................................................................................................................... 7 E.6.7 Effects on the Wastewater Network ........................................................................................................ 7
E.7 Auckland’s Vision for Stormwater Management ................................................................................................ 8 E.7.1 Auckland Plan ........................................................................................................................................... 8 E.7.2 Water Sensitive Community .................................................................................................................... 8
E.8 Auckland NDC Outcomes .................................................................................................................................... 9 E.8.1 Outcomes ................................................................................................................................................. 9
E.9 Consultation ........................................................................................................................................................ 9 E.9.1 Consultation Process ................................................................................................................................ 9 E.9.2 Summary of Consultation Outcomes and their Proposed Management ............................................... 13
E.10 Auckland NDC – Best Practicable Option (BPO) ................................................................................................ 13 E.10.1 Implementation Methods ...................................................................................................................... 13 E.10.2 Management of Future Changes to and Development of the Network ................................................ 15
E.11 Assessing Progress Towards Outcomes - Six-year Targets ................................................................................ 16
E.12 Monitoring and Review ..................................................................................................................................... 16 E.12.1 Monitoring ............................................................................................................................................. 16 E.12.2 Review Process ...................................................................................................................................... 17
E.13 Conditions of Consent ....................................................................................................................................... 19
List of Tables
Table 1: Auckland Stormwater NDC Outcomes and Key Stormwater Management Issues ........................................ 10
Table 2: Auckland Stormwater NDC – BPO Implementation Mechanisms.................................................................. 14
List of Figures
Figure 1: Map of the ‘urban’ area covered by the Auckland Stormwater NDC ............................................................. 4
Figure 2: Implementation, Monitoring and Review .................................................................................................... 18
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Attachments
Attachment 1: NDC Objectives, Outcomes and Six-year Targets
Attachment 2: Auckland Stormwater NDC Works, Connections and Vesting Performance Requirements
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Executive Summary
E.1 Background
Most of Auckland’s urban area and rural and coastal settlements are serviced by a public stormwater network, owned
by Auckland Council. Council’s Healthy Waters Department (Healthy Waters) is responsible for the operation,
maintenance and on-going development of the public stormwater network, which is essential infrastructure in an
urban environment. The network provides for the health, safety and well-being of the community and provides for
the functioning of communities, businesses and industries within Auckland by minimising flood risk, providing the safe
conveyance of stormwater away from buildings and property and minimising adverse environmental effects.
The public stormwater network is extensive and complex and is described in detail in Council’s Stormwater Asset
Management Plan, 2015 – 2045 (2015)1.
Auckland’s built public stormwater network includes approximately:
▪ 6,000 km of pipelines (pipes and culverts);
▪ 145,000 manholes;
▪ 377 km of lined and unlined channels (not including roadside drains);
▪ 6,700 catchpits;
▪ 25,000 outlets and inlets structures; and
▪ Over 900 stormwater detention and treatment facilities.
Hard infrastructure assets, such as pipes, are typically designed to serve a single function: the conveyance of
stormwater into streams and rivers, aquifers or directly into the marine environment and have limited adaptability.
Green infrastructure assets such as ponds, wetlands and swales, can either be constructed or enhanced natural
features. They often have multiple functions beyond the conveyance of stormwater, including amenity (wetlands and
ponds are often part of a wider recreational reserve) and broader ecological benefits.
Natural assets and landforms including streams, overland flowpaths, floodplains and groundwater aquifers are also an
essential part of the wider stormwater system and must be managed in conjunction with the built network.
Stormwater is often piped to the nearest stream or directed to shallow groundwater aquifers (where these are
suitable) for conveyance to the coast or discharged directly into marine environments. Where the capacity of the
network is exceeded, stormwater is conveyed via overland flow paths and flood plains that provide temporary storage
as well as conveyance until flood flows subside. Natural assets can be located on both private and public property.
Stormwater management in the Auckland region continues to evolve. While the focus of past stormwater
infrastructure management was primarily the management of flooding, over the last 50 years contaminant reduction
and removal and the protection of streams and associated ecosystems has gained greater prominence. This is due to a
better understanding of the adverse effects that the conveyance and disposal of stormwater can have on aquatic
receiving environments (both coastal and freshwater).
This evolution has recognised the integral role that land use and development play in the generation of stormwater
and associated contaminants. A more integrated approach involving the management of land use activities, including
implementing stormwater management at source, is essential to achieve more effective management of potential
stormwater related adverse effects. This has multiple positive environmental and community outcomes and is a more
comprehensive approach than traditional “end of pipe” management. Integrated stormwater management
contributes to “green growth”, sustainability and the reviving of degraded receiving environments, while continuing to
meet levels of service that have been established, consistent with the aspirations of the Auckland Plan.
1Appendix A
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E.2 Auckland Stormwater NDC
In accordance with the requirements of the Resource Management Act 1991 (RMA), and the provisions of the
Auckland Unitary Plan (Operative in Part)2, resource consent is required for the diversion and discharge of stormwater
from the public stormwater network and the impervious areas that contribute to them. Currently, stormwater
network diversions and discharges are authorised by a variety of existing authorisations and resource consents
inherited from Auckland’s seven previous territorial authorities and private stormwater discharge consents that have
been transferred to Council. These authorisations vary in their age and the activities they cover and, importantly,
stormwater discharges from approximately half of Auckland’s urban area are subject to consent applications that are
more than 15 years old, some of which have not been significantly progressed.
This “patchwork” of consents and other authorisations is complex, inefficient and confusing, and leads to inconsistent
stormwater management requirements across Auckland. In addition, the age of many of the older consents is such
that they no longer represent current best practice, may not be relevant to the stormwater infrastructure needs of the
area and may even be counter-productive to achieving stormwater management outcomes that are in accordance
with the Auckland Unitary Plan and relevant national statutory instruments.
The Auckland Stormwater NDC, once granted, will replace these multiple authorisations with a comprehensive set of
regionally consistent requirements to deliver the outcomes specified in the consent and aligned with the Auckland
Plan and Auckland Unitary Plan.
E.3 Activities for Which Resource Consent is Sought
The activities for which consent is sought under the Auckland Stormwater NDC are:
▪ The diversion of stormwater from both existing and future urban land uses within the Rural Urban Boundary
(RUB), urban areas outside of the RUB, coastal and rural settlements and other areas that are serviced by the
public stormwater network (either currently or in the future) (Figure 1). This includes runoff from Auckland
Transport and New Zealand Transport Agency State Highway road networks that divert stormwater to the
Council stormwater network. Note that future urban areas are only incorporated into the Auckland
Stormwater NDC once they are urbanised and a stormwater network is developed.
▪ Discharges of stormwater from the Council’s stormwater network to land, rivers/streams, lakes, groundwater
aquifers and the Coastal Marine Area.
Importantly, the Auckland Stormwater NDC seeks to authorise not only the current stormwater network and its
associated discharges, but future stormwater discharges that arise from changes to the stormwater network. This
includes diversions and discharges from future growth and development – both new greenfield development and
intensification.
For clarity, the Auckland Stormwater NDC application does not include the following:
▪ Private stormwater diversions and discharges that do not enter the public network. These are separately
regulated by the Auckland Unitary Plan.
▪ Diversion and discharges from Auckland Transport and New Zealand Transport Agency State Highway roading
networks that do not enter the Council owned and operated network.
▪ Resource consents for structures and other stormwater operational activities. These will be developed or
undertaken in accordance with permitted activity requirements or otherwise subject to a separate resource
consent(s).
▪ Point source contaminant discharges that are discharged to the stormwater network from other activities such
as wastewater overflows, pollutant discharges from industrial sites and closed landfills and sediment
discharges from urban development. These are separately regulated by the Auckland Unitary Plan.
A 35-year consent term is sought, which is commensurate with the scale and significance of Auckland’s public
stormwater network, its capital value and the level of on-going investment required in developing and improving the
2 Subsequently referred to as the Auckland Unitary Plan in this application as the provisions pertaining to the Auckland Stormwater NDC are operative
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network. Notwithstanding this, a six-yearly review is provided for in the proposed conditions of consent to ensure
that the Auckland Stormwater NDC remains current as community aspirations and best practice continue to evolve.
E.4 Auckland Stormwater NDC Aims
The aims of the Auckland Stormwater NDC are to:
▪ Provide for the regional planning, operation, renewal, upgrade and on-going development of Auckland’s
stormwater network to meet development needs, community expectations and agreed levels of service while
minimising adverse effects to the extent reasonably practicable.
▪ Progressively reduce adverse effects from the existing network/urban development while ensuring new
adverse effects from future development and network expansion are prevented or minimised, in accordance
with the Best Practicable Option (BPO) and other relevant considerations of the Auckland Unitary Plan and
other statutory instruments.
▪ Assist in prioritising resources and investment so that they are focussed on achieving the best overall outcomes
for the community and natural environment at both a regional and local scale in line with the vision for the
region, as articulated in the Auckland Plan and the provisions of the Auckland Unitary Plan.
▪ Facilitate future growth and development under an Auckland-wide consent framework that provides clarity
and consistent requirements to land developers who connect to the public stormwater network or whose
stormwater infrastructure will ultimately become part of the public network, once it is constructed and vested.
▪ Replace the many, different consent and other authorisations that currently exist across the region with a
single resource consent to simplify requirements and enable current best practice to be implemented.
▪ Provide for processes of continuous improvement and adaptive management to respond to inevitable changes
in the statutory framework, technology, knowledge and community priorities.
▪ Establish monitoring and regular review processes to enable achievements and progress to be monitored and
reported and ensure that the Auckland Stormwater NDC remains current and relevant over time.
E.5 Key Stormwater Management Issues
The public stormwater network is extensive and complex and the nature, performance and adverse effects of the
network vary across Auckland. To encapsulate the Auckland Stormwater NDC application into a manageable and
understandable form, seven key issues have been identified as arising from the development and operation of the
stormwater network as follows:
1. Managing Assets – the ability to develop, operate and maintain essential stormwater infrastructure that
provides for the current and future needs of the community.
2. Effects of Growth – the ability to service the significant future growth of Auckland, including intensification,
while preventing or minimising the stormwater related adverse effects of new growth and progressively
reducing existing adverse effects and restoring degraded environments where practicable.
3. Flood Effects – the extent of flood hazards, including overland flow, and the potential effects on and risk to
communities, houses and other buildings/infrastructure.
4. Effects on Stream Health – the effects of stormwater flows, and associated infrastructure, on stream erosion,
water and sediment quality and freshwater ecosystems.
5. Effects on Coastal Health – primarily the accumulation of contaminants carried in stormwater flows from urban
areas and deposited in marine sediments and associated adverse effects on marine ecosystems, particularly in
estuarine and upper harbour areas.
6. Effects on Groundwater – the loss of aquifer recharge and, where stormwater is directed to groundwater
aquifers, the potential for adverse effects on groundwater quality and aquifer capacity.
7. Effects on the Wastewater Network – the interaction with the wastewater and combined networks owned and
operated by Watercare Services Limited.
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Figure 1: Map of the ‘urban’ area covered by the Auckland Stormwater NDC
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It is recognised that stormwater diversion and discharges can adversely affect cultural and community values. The
potential impact of stormwater on these values, particularly the mauri of water and Te Mana o te Wai, are an integral
component of the identified issues and hence have not been identified separately.
These priority issues formed the basis of significant consultation with mana whenua, stakeholders and the community
and the associated basis for developing the NDC Outcomes and Targets and the BPO.
E.6 Effects of Diversions and Discharges from the Stormwater Network
The development of a stormwater network goes hand-in-hand with the development of urban areas. Stormwater
infrastructure, whether built or green, is essential to capture and convey stormwater and discharge it in a managed
way. That is, a stormwater network is a fundamental building block of any urban area and assists in enabling ‘people
and communities to provide for their social, economic, and cultural well-being and for their health and safety’ in
accordance with the sustainable management purpose and principles of the RMA.
Notwithstanding this, the manner in which stormwater is diverted and discharged can also give rise to adverse effects
on both the communities and natural environments they are designed to protect. Over the past three decades,
stormwater has been a focus of significant research and monitoring undertaken by the then Auckland Regional Council
(ARC), previous territorial authorities and more latterly by the Auckland Council; government agencies; and private
parties. This large body of work has led to a good understanding of the adverse effects of discharges from Auckland’s
stormwater network, although the knowledge base and understanding will inevitably continue to grow as more
monitoring and studies are undertaken.
An assessment of adverse effects is incorporated into the Auckland Stormwater NDC application. A summary of the
adverse effects associated with the seven key issues identified above, is provided as follows.
E.6.1 Stormwater Assets
In addition to the effects of stormwater discharges, stormwater assets such as outfalls and culverts can also affect
receiving environments such as streams and the coastal environment, for example by restricting stream flows and
being subject to erosion, particularly at the edges of hard engineered structures. These adverse effects are generally
localised. Inspection and maintenance are critical methods to ensure structures perform properly while minimising
adverse effects. Poorly designed and maintained assets can also potentially affect public access to and along rivers
and streams.
Devices such as ponds, as well as highly modified channels, can also contribute to increases in stream temperature,
which has recently been identified as a potential effect on freshwater ecosystem health in Auckland.
E.6.2 Effects of Growth
The Auckland Plan has outlined future growth for the Auckland region projecting significant increases in population
and employment, through a combination of intensification within the existing rural urban boundary (60 to 70% of
growth) and expansion into new greenfield areas (30 to 40 % of growth). While the exact distribution and extent of
growth will be determined by the implementation of the Auckland Unitary Plan and market drivers, it is anticipated
that significant intensification and greenfield growth will occur.
Growth provides both challenges and opportunities for achieving stormwater management outcomes including:
▪ The potential to increase existing adverse effects (intensification) or create new adverse effects (particularly in
new growth areas);
▪ Optimising the use of existing stormwater infrastructure and providing for the timely replacement, renewal and
upgrading of existing infrastructure to meet growth needs;
▪ Ensuring that new infrastructure is fit for purpose and meets Council’s requirements, including providing
capacity to accommodate additional future growth and effects of climate change;
▪ Locating and designing new development in a way that minimises the creation of new adverse effects; and
▪ Taking the opportunities provided by redevelopment to improve stormwater management and progressively
reduce existing adverse environmental effects and enhance degraded environments.
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E.6.3 Flooding
Flooding is one of the most significant and frequent natural hazards in the Auckland region. It is estimated that there
are some 137,000 buildings potentially affected by some form of flooding in a 1% Annual Exceedence Probability
(AEP)3 flood event:
▪ 52,000 buildings within the 1% AEP floodplain, of which 8,000 are at risk of flooding above floor level.
▪ 65,000 buildings within identified 1% AEP overland flow paths of which 7,000 are at risk of flooding above the
floor level.
▪ 20,000 buildings within flood prone areas of which 1,000 are at risk of flooding above the floor level.
Flood risk needs to be managed and mitigated to avoid loss of human life, protect buildings and property, minimise
disruption to significant infrastructure and facilities, and minimise social and economic costs. Appropriate location of,
and management of stormwater from, new development and re-development have a significant role to play in
managing flood risk to ensure that existing flood risks are not increased and are decreased where possible.
Climate change is likely to increase the frequency and magnitude of high intensity rainfall events, which may further
exacerbate flood risk and directly impact on infrastructure and development across Auckland including the operation
of stormwater systems, level of service for roads and bridge culverts and development of lower lying land.
E.6.4 Effects on Stream Health
There is an increasing body of information on the nature of adverse effects on stream health associated with the
process of urbanisation and the development of impervious areas.
Auckland’s urban streams are subject to significant stormwater discharges and show responses that are consistent
with those found both nationally and internationally. These responses are not a result of any one single factor, but of
the multiple stressors associated with urban development including changes in hydrology (such as increased peak
flows and reduced base flows), the introduction of “urban” contaminants, the fragmentation of streams through
piping and physical changes to stream banks and channels. The latter include the introduction of structures and
accelerated stream erosion associated with increased stormwater flows.
In summary, Auckland urban streams:
▪ Typically have “fair” water quality, but range from poor to good, as measured by the Auckland Council’s water
quality index; and dissolved metal concentrations that generally exceed recognised guidelines for the
protection of stream ecosystem health.
▪ Appear to show a slight decreasing trend in metal and sediment concentrations over time, consistent with
expectations regarding reduced contaminant loads (particularly sediment and zinc).
▪ Have poor to fair Macro-Invertebrate Community Index (MCI) Scores (an indicator of ecological health),
consistent with expectations based on catchment imperviousness.
▪ Support a range of native fish species, including some that are recognised as “threatened” by the Department
of Conservation.
▪ Have a range of management issues and opportunities for mitigation and enhancement associated with both
the stormwater network and associated structures and on council –owned and private land.
While all urban streams will demonstrate the above adverse effects to a greater or lesser extent, streams in
catchments that have yet to undergo significant urbanisation or which have retained significant in-stream values have
the potential to have their ecological values maintained and enhanced. Effective management and mitigation of
hydrological change during urbanisation is fundamental to achieving this.
E.6.5 Effects on coastal health
As is the case with streams, a large body of data has been generated through monitoring the regional marine
environment (water quality, sediments, ecology) and, in the case of sediment, has been used to predict future trends
for typical ‘urban’ contaminants being copper, lead, zinc and high molecular weight PAH4s. This information indicates
3 A 1% AEP Flood event has a 1% chance of occurring in any given year – or on average, will occur once in every hundred years 4 Polycyclic Aromatic Hydrocarbons
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that the marine receiving environment, especially the low energy inner-harbour systems, are impacted by stormwater
runoff. In summary, the marine receiving environment exhibits the following characteristics:
▪ Open coastal sites have the highest water quality, reflecting a high degree of flushing and distance from
freshwater inputs.
▪ Marine sediment contamination is most significant in the Central and Upper Waitematā Harbour, the mid to
upper Tāmaki Estuary and the Mangere Inlet where the majority of the monitoring sites are identified as either
having red (high) or amber (moderate) contaminant levels under Auckland Council’s Environmental Response
Criteria (ERC) classification system. The remaining monitoring sites, typically in areas of more recent
development or on the fringes of the urban area, are identified as green (low) levels of contaminants under the
ERC classification.
▪ Analysis of the accumulation of contaminants in sediment over time has concluded there are relatively few
consistent significant trends, however in brief:
No consistent spatial pattern of trends was shown for copper, with decreases generally outnumbering increases, suggesting generally decreasing concentrations.
Lead exhibits generally decreasing trends in urban estuaries, particularly in the older developed catchments of the Central Waitematā Harbour, Tāmaki Estuary, and Mangere Inlet. This is likely to be associated with removal of leaded petrol and paint from the New Zealand market some 15 years ago.
Zinc concentrations appear to have increased in the Whau Estuary (Central Waitematā Harbour) and the Tāmaki Estuary, but decreased in Mangere Inlet, and a mixture of increases and decreases have occurred elsewhere. Overall, increases have outnumbered decreases.
PAH concentrations are generally low, and showed moderate variability although the number of samples was small.
▪ Marine ecological health shows a similar pattern to that of sediment contaminant metals, with typically
moderate to poor health (a benthic health grade of 3 - Moderate to poor) in upper estuaries and harbours
adjacent to urban areas. However ecological communities can also be degraded in estuaries outside the urban
areas (with benthic health grades of 3 to 4), which is likely to be a consequence of freshwater or sediment
related adverse effects such as increased “muddiness”.
E.6.6 Effects on Groundwater
The two groundwater aquifer systems in the region most subject to network stormwater discharges are the relatively
shallow Auckland Isthmus volcanic and the Pukekohe volcanic aquifers. Ground soakage, as an alternative to
reticulated stormwater networks, is an essential element of stormwater management on the Auckland Isthmus in
those parts underlain by shallow basalt aquifers.
In addition to being a primary method of stormwater disposal, discharges to ground soakage play an important role in
groundwater recharge to sustain groundwater abstractions (such as Watercare Services Ltd take for water supply in
Onehunga and abstraction for horticultural purposes in Pukekohe) and stream base flows. For example, stormwater
network discharges account for approximately 25% of recharge to the Auckland Isthmus basalt aquifers.
Water quality data recorded for the areas indicates that water quality within the aquifer, particularly the Auckland
Isthmus Volcanics, generally meets drinking water standards but may not meet these standards in some locations.
However, these exceedances may not be the result of stormwater discharges, as the soil and rock matrix is
demonstrated to be effective at removing a significant proportion of stormwater contaminants during soakage. Most
likely, the exceedances are the result of a combination of stormwater discharges and point sources of contaminants
such as industrial site discharges to ground, contaminated sites and landfills.
Groundwater breakout is evident in parts of the Auckland Isthmus resulting in water ponding in low lying areas, or
water being forced under hydraulic pressure through local confining surfaces. Such flows have been known to occur
through cracks in concrete building floors in the lower Onehunga area during wet periods when aquifer water levels
are at their highest.
E.6.7 Effects on the Wastewater Network
Discharges of untreated wastewater to land, streams and the coast generally occur as a result of the network
overflowing, when flows exceed the capacity of the network and a mix of stormwater and wastewater is forced out of
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the system. This can also occur under dry weather conditions, due to pipe constrictions and network breakdowns, but
most commonly during wet weather. Management of overflows and associated adverse effects is the responsibility of
Watercare Services Ltd, although stormwater ingress in these networks contributes to overflows. In some cases,
works within both the stormwater and wastewater networks may be required to reduce overflows.
E.7 Auckland’s Vision for Stormwater Management
E.7.1 Auckland Plan
The Auckland Plan provides an important context for the future growth and development of, and the issues that face,
Auckland. It sets a vision for Auckland of being “the World’s most liveable city”. This vision is given effect to by a
series of outcomes, strategic directions, directives and transformational shifts undertaken in the context of the
overarching principles of the plan. Effective stormwater management contributes to multiple outcomes and
directives across the Auckland Plan.
The Auckland Plan recognises that preserving marine and fresh water quality is fundamental to Auckland’s future.
Auckland’s water features have significant community, natural and cultural values and past development has put
pressure on water resources and resulted in major hydrological changes. Over the last century, stormwater
management in urban areas and drainage and diversion for rural production have reduced water quality and
ecological function within catchments and degraded coastal receiving environments. However, the effects of land use
development and stormwater runoff and how to manage and reduce them is now better understood.
Connectivity is a key consideration. Freshwater not only maintains life in catchments but feeds marine life in river
mouths, and estuaries and streams provide access for fish spawning. Water quality, aquatic life, amenity and access
can be improved. Riparian rehabilitation is needed and can result in multiple benefits including improving
environmental, social, and economic outcomes and reducing net carbon emissions. While the diversion and discharge
of stormwater cannot be avoided, it is possible to improve water quality and the values of urban streams and coastal
areas where these have been degraded.
The Auckland Plan also recognises that infrastructure is critical to the economic, social, environmental and cultural
well-being of Auckland and the importance of stormwater networks as a component of ‘Auckland-wide defining
infrastructure’. It identifies the need to address existing problems and issues, including flooding, water quality
degradation and the effects of diversions and discharges on ecosystems and biodiversity. Integrated management
within whole catchments is a primary mechanism to achieve these multiple outcomes and to sequence infrastructure
provision and upgrading to meet growth needs. The Auckland Plan also signals a move to more sustainable ‘green
growth’, with a focus on avoiding and minimising adverse effects through water sensitive design in both new and re-
development and the provision of quality infrastructure including green infrastructure.
E.7.2 Water Sensitive Community
To assist in achieving the multiple outcomes of the Auckland Plan, Healthy Waters has established the vision of a
‘Water Sensitive Community’. From a stormwater perspective, the concept of a water sensitivity community
recognises the value of stormwater, its close interrelationship with natural freshwater systems and cultural values,
and how it can enhance the liveability of our cities. The evolution to a water sensitive community is a significant shift
from the past stormwater management approach of removing and disposing of stormwater as fast as possible via built
infrastructure. While built infrastructure has always been a primary component of Auckland’s network, and its on-
going efficient and effective operation and renewal is fundamental to sustainable stormwater management, built and
natural assets need to be managed in an integrated way to avoid, remedy and mitigate environmental effects and
achieve multiple community outcomes in a more intensively developed city.
To focus its business on achieving the vision of a water sensitive community, Healthy Waters has established three
core and four supporting objectives which are strongly connected to the Auckland Plan strategic directions and
relevant provisions of the Auckland Unitary Plan:
Safe Communities: Risk to our communities, including people, property and infrastructure is reduced. Our objective
is to ensure that risk to people and property is managed to levels that have been established in consultation with the
community, and reduce existing flood risk where it is above these levels.
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Supporting Growth: Growth through water sensitive development and provision of quality stormwater infrastructure
is enabled. Our objective is that new and re-developed areas are supported by effective stormwater management
and good quality infrastructure and development is undertaken in a way that meets the needs of our communities
and maintains and enhances natural water systems.
Healthy and Connected Waterways: Stream, groundwater and coastal water values are maintained and enhanced
and communities are connected with them. Our objective is to utilise streams, aquifers and harbours as integral
natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on,
and enhancing our community’s connection with, its waterways.
Collaborative Outcomes: Stakeholders are engaged to achieve the best stormwater outcomes for present and future
generations.
Efficient Business: Robust systems, processes, practices and management are implemented to support delivery of
stormwater services.
Prioritised Investment: Benefits from limited resources are maximised by targeting our priorities to achieve the best
outcomes we can afford.
High Performing Teams: Our people’s ability to adapt and grow is valued, enabling them to achieve top results as part
of a dynamic team.
E.8 Auckland NDC Outcomes
E.8.1 Outcomes
Outcomes have been developed for the Auckland Stormwater NDC to give effect to the strategic vision. These
outcomes also give effect to the objectives and policies of the Auckland Unitary Plan, which provides the statutory
framework against which the Auckland Stormwater NDC application is assessed.
The NDC Outcomes form the basis of the consent in terms of the community, environmental and cultural outcomes
that are sought over the duration of the 35 year consent. The stormwater management issues and associated NDC
Objectives, Outcomes and six-year targets are provided in Attachment 1.
The relationship between the stormwater management outcomes and the key stormwater management issues is
shown in Table 1.
E.9 Consultation
E.9.1 Consultation Process
Healthy Waters has undertaken a significant engagement process to enable informed input from iwi, other
stakeholders and the public into the NDC Outcomes and to help guide priorities for the development of the best
practicable option. Engagement processes included:
1. Identification of Stormwater Management Priorities. This consultation was focused on the four Consolidated
Receiving Environments (CREs) with the largest urban areas: The Waitematā Harbour, Greater Tāmaki,
Manukau Harbour and Hibiscus / East Coast Bays CREs. This initiative, completed between 2012 and 2015,
invited over 200 stakeholders to participate in providing what they considered to be priority stormwater
management issues for each CRE, and how these issues should best be managed. The consultation was
specifically commissioned to feed into the NDC application, in particular the BPO assessment in accordance
with the seven key issues identified in this NDC application.
2. Consultation on NDC Framework. This consultation focused on the NDC framework itself and sought feedback
from the 21 Auckland Council Local Boards, iwi, Auckland Regional Public Health Service, and Auckland Council
Parks (which specifically expressed interest in the application). This initiative began in February 2015 and was
completed in October 2015. Outputs from this process included specific amendments sought from the
stakeholders to the NDC objectives, outcome and targets and general feedback on the seven stormwater
management issues.
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Table 1: Auckland Stormwater NDC Outcomes and Key Stormwater Management Issues
✓ = strong relationship; ✓ = moderate relationship
Management Objective and NDC Outcomes Assets Growth Flooding Streams Coastal Ground water
Waste water
Safe Communities:
Risk to our communities, including people, property and infrastructure is reduced - ensure that risk to people and property is managed to levels that have been established in consultation with the community, and reduce existing flood risk where it is above these levels
ND
C O
utc
om
es
Manage existing public stormwater assets to meet agreed levels of service ✓ ✓ ✓ ✓ ✓ ✓ ✓
Manage erosion effects caused by discharges through public stormwater infrastructure ✓ ✓ ✓ ✓
Improve existing assets by taking the opportunities from redevelopment where they arise ✓ ✓
Avoid the increase of existing flooding or creation of new flooding of habitable floors as a result of urban development and intensification
✓ ✓ ✓
Reduce existing flood risk by taking the opportunities from redevelopment where they arise ✓ ✓ ✓
Manage existing flood risk to meet levels of service agreed to keep people and property safe from significant harm from flooding, and minimise disruption to critical social and physical infrastructure connections across the city
✓ ✓ ✓
Improved community understanding of, and resilience to, flood hazards ✓ ✓ ✓
Supporting Growth
Growth through water sensitive development and provision of quality stormwater infrastructure is enabled - new and re-developed areas are supported by effective stormwater management and good quality infrastructure and development is undertaken in a way that meets the needs of our communities and maintains and enhances natural water systems
ND
C O
utc
om
es
Align stormwater infrastructure planning to development and intensification priorities ✓ ✓ ✓ ✓ ✓ ✓ ✓
Integrate water sensitive design into new and major re-development. This can include promoting source control, at source treatment, bioretention, detention and attenuation, and protection and enhancement of streams
✓ ✓ ✓ ✓ ✓ ✓
Enable effective land use and stormwater management planning and co-operation between developers and infrastructure providers
✓ ✓ ✓
Establish clear standards and processes for the planning, development and vesting of good quality public stormwater infrastructure, particularly in terms of minimising operational and renewal costs, as well as minimising community, environmental and cultural effects
✓ ✓ ✓ ✓ ✓ ✓
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Management Objective and NDC Outcomes Assets Growth Flooding Streams Coastal Ground water
Waste water
Healthy and Connected Waterways
Stream, groundwater and coastal water values are maintained and enhanced and communities are connected with them - utilise streams, aquifers and harbours as integral natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on, and enhancing our community’s connection with, its waterways
ND
C O
utc
om
es Maintain, operate and develop Council’s current and future public stormwater network to
minimise and reduce adverse effects on streams, groundwater and coastal systems ✓ ✓ ✓ ✓ ✓
Enhance urban waterways by working collaboratively with key stakeholders such as mana whenua, Local Boards, community groups and the development community to take opportunities where they arise
✓ ✓ ✓ ✓ ✓ ✓
Collaborative Outcomes
Stakeholders are engaged to achieve the best stormwater outcomes for present and future generations
ND
C O
utc
om
es
Collaborate with Council departments and CCOs that have a key role in delivering positive stormwater outcomes
✓ ✓ ✓ ✓ ✓ ✓ ✓
Build constructive, working relationships with key stakeholders to achieve integrated stormwater solutions and cost effective outcomes
✓ ✓ ✓ ✓ ✓ ✓ ✓
Establish effective mechanisms for mana whenua to be appropriately engaged in stormwater management. This includes recognising and actively working to operationalise and integrate the relationship and cultural values mana whenua have with their waterways
✓ ✓ ✓ ✓ ✓ ✓ ✓
Work with the stormwater industry to continue to identify, refine and communicate best practice and increase industry capacity, resources and knowledge
✓ ✓ ✓ ✓ ✓ ✓
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Management Objective and NDC Outcomes Assets Growth Flooding Streams Coastal Ground water
Waste water
Efficient Business
Robust systems, processes, practices and management are implemented to support delivery of stormwater services
ND
C O
utc
om
es
Undertake efficient and effective network operational, renewals and maintenance programmes
✓ ✓ ✓ ✓ ✓ ✓
Regionalise stormwater management through harmonisation of standards, contracts and business processes
✓ ✓ ✓ ✓ ✓ ✓
Provide fit for purpose information systems and business tools ✓ ✓ ✓ ✓ ✓ ✓
Undertake efficient and effective response to customers and incidents ✓ ✓ ✓ ✓ ✓ ✓
Rationalise network consents and compliance requirements ✓ ✓ ✓ ✓ ✓ ✓
Monitor and report performance ✓ ✓ ✓ ✓ ✓ ✓ ✓
Prioritised Investment
Benefits from limited resources are maximised by targeting our priorities to achieve the best outcomes we can afford
ND
C O
utc
om
es
Undertake regional prioritisation that targets investment in the right areas, as agreed within Council, with mana whenua, and with our community and in accordance with the Auckland Plan vision and statutory requirements
✓ ✓ ✓ ✓ ✓ ✓ ✓
Establish levels of service that are relevant and affordable
✓ ✓ ✓ ✓ ✓ ✓ ✓
High Performing Teams:
Our people’s ability to adapt and grow is valued, enabling them to achieve top results as part of a dynamic team
✓ ✓ ✓ ✓ ✓ ✓ ✓
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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3. Feedback received from Heathy Waters’ Customer Service Survey. As part of a three-year stormwater
education plan proposed to inform Aucklanders on how they can contribute to building a water sensitive
community, Healthy Waters engaged Colmar Brunton to undertake research into understanding how
residents currently feel about stormwater, and how much they know and understand.
4. Public Consultation on Council’s Long Term Plan. Around 230 feedback comments relating to stormwater
management were received as part of public consultation completed for Council’s Long Term Plan 20155.
Based on the consistency of feedback received from stakeholders across this engagement and consultation, it can
be concluded that the consultation provides significant confidence that key stormwater issues have been both
identified and prioritised. This was acknowledged by the stakeholders who participated in the CRE based
consultation as follows:
▪ During the first consultation exercise for the Waitematā Harbour CRE, external stakeholders raised several
additional issues to those initially identified in the material presented. These included the need to manage
green infrastructure differently than underground infrastructure, and to bring in the cultural values of mauri.
These additional issues were incorporated into material and presentations for the latter consultation in the
Greater Tāmaki, Manukau and Hibiscus and East Coast Bay CREs.
▪ No additional significant issues were raised during subsequent consultation, indicating that the matters that
are of material concern to the stakeholders in relation to stormwater management have been identified.
This consultation has therefore resulted in delivering a robust, comprehensive and transparent process and
contributing to a comprehensive consent application.
Healthy Waters is committed to continuing the development of strong relationships with its stakeholders. As such,
stakeholder consultation will be on-going throughout the life of the Auckland Stormwater NDC, particularly as
implementation moves from the high-level consent to detailed studies and project-based consents. The
relationships that have been developed now will therefore be strengthened through these future consultation
initiatives.
E.9.2 Summary of Consultation Outcomes and their Proposed Management
A key part of any consultation process is ensuring that the feedback received from stakeholders is considered and
influences the stormwater management options and outcomes. This has been achieved by:
▪ Stakeholder feedback received during the CRE based engagement on the prioritisation of stormwater
management issues, was directly used in the assessment of options to determine the regional BPO for
managing stormwater discharges from the network.
▪ The proposed NDC Objectives, Outcomes and Targets, were amended as a result of the feedback received.
▪ Management approaches to deal with key issues identified during the consultation are or will be in place.
E.10 Auckland NDC – Best Practicable Option (BPO)
E.10.1 Implementation Methods
Policy E 1.3.14 of the Auckland Unitary Plan requires the adoption of the BPO to minimise the adverse effects of
stormwater discharges from stormwater network. Importantly, the requirement to adopt the BPO sits alongside
other objectives and policies that relate to stormwater management and associated social, cultural and
environmental outcomes. Accordingly, the BPO must be developed in the context of the wider objectives and
policies of the Auckland Unitary Plan, together with the specific requirements of Policy E 1.3.14.
The BPO at an Auckland-wide level represents the best mixture of a range of techniques to prevent or minimise the
adverse effects of discharges from the public stormwater network to deliver the NDC Outcomes – which have been
developed to give effect to the direction provided by the Auckland Plan and in accordance with the Auckland
Unitary Plan. This multi-faceted approach recognises that the effective management of stormwater and mitigation
of adverse effects cannot solely be undertaken at a network level, but requires a range of actions to be undertaken
5 The Current LTP is Te Tahua Taungahuru - Te Mahere Taungahuru (10-Year Budget and Long Term Plan) 2015-2025
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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at different scales and by different parties to appropriately manage, minimise and, where practicable, reduce
existing stormwater-related adverse effects. This includes the management of land use to prevent and minimise
the generation of stormwater and associated contaminants at source through the Auckland Unitary Plan.
The BPO for the Auckland Stormwater NDC therefore incorporates not only the works that Healthy Waters
implements through its asset management and capital investment programme, but also those which it requires or
seeks to influence through other processes as shown in Table 2.
Table 2: Auckland Stormwater NDC – BPO Implementation Mechanisms
Direct Control (DC):
Projects or programmes that are within the ability of Healthy Waters to implement, subject to prioritisation and budget. This is implemented through the processes described in Section 9.
Implementation Mechanisms:
Capital works programme
Operations and maintenance programme
Asset renewals
Stormwater enhancement/rehabilitation projects
Collaborate (Co):
Projects or programmes that are partially within the ability of Healthy Waters to implement (subject to budget and prioritisation), but require consultation and alignment of priorities with other parties. Healthy Waters implements this component of the BPO through the processes described in Section 9 and Appendix A, but their implementation requires the contribution and commitment of other parties.
Implementation Mechanisms:
Joint projects with Watercare, Auckland Transport, Parks etc
Cross Council projects (often catchment or sub-catchment based)
Enhancement projects with iwi and community
Indirect Control (IC):
Measures or requirements that Healthy Waters can seek to direct through statutory and other tools, but for which it cannot completely ensure the outcome as they are subject to other statutory processes. For example, Healthy Waters may implement this component of the BPO through the statutory provisions and requirements in the Auckland Unitary Plan, which are then implemented through processes such as private resource consents.
Implementation Mechanisms:
Stormwater management provisions in Unitary Plan (implemented by Council’s regulatory department)
Stormwater Code of Practice
Stormwater Bylaw connection standards
Influence (In):
Measures or requirements that are outside of the scope of Healthy Waters’ ability to implement or direct for which it can only influence. Healthy Waters implements this element of the BPO through processes such as advocacy, education and facilitation.
Implementation Mechanisms:
National source control initiatives
Community based enhancement projects
Non-regulatory improvements
Future implementation of the National Policy Statement for Freshwater Management, 2014
In addition to Healthy Water’s capital investment programme, implementation includes:
▪ The Auckland Unitary Plan. This includes requirements for:
Private (non-network and network) stormwater diversions and discharges;
Management of high contaminant generating activities;
Flow management in stream catchments that are sensitive to increases in stormwater flows;
Flood hazard management including development and redevelopment within flood plains and the management of overland flow;
Management of activities in/diversion/reclamation of rivers and streams;
Stormwater management requirements, including the implementation of an Integrated Stormwater Management/water sensitive design approach, for subdivision.
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▪ The Auckland Council Code of Practice for Land Development and Sub-Division: Chapter 4 – Stormwater
(Stormwater Code of Practice). The Stormwater Code of Practice provides minimum standards for the
design and construction of new public stormwater networks and infrastructure, including those built by
Council and those constructed as part of development and subsequently vested in Council.
▪ The Auckland Council Stormwater Bylaw. The Stormwater Bylaw regulates land drainage and protects and
manages the development, maintenance and use of the public stormwater network (and associated land,
overland flow paths and structures), and ensures that discharges into the public stormwater network do not
damage the network or compromise the council’s ability to comply with any applicable network discharge
consent. This is primarily achieved through requirements on new (vested) infrastructure, connections to the
network, works in the vicinity of the network, controls on the obstruction or diversion of stormwater and
maintenance of private networks.
▪ The provision of guidance information.
▪ Collaborative projects with other organisations, for example Watercare Services Limited, New Zealand
Transport Agency and Auckland Transport.
▪ Engagement with iwi and the community on enhancement projects.
E.10.2 Management of Future Changes to and Development of the Network
The diversion and discharge of stormwater from the public stormwater network will continue to change over time,
primarily due to:
1. Asset renewal and maintenance, and improvements to the performance of the stormwater network (ie flood
mitigation or stormwater quality treatment), undertaken by Healthy Waters.
2. The development of new/changes to existing impervious areas associated with intensification and
brownfield redevelopment, where these areas discharge to the stormwater network or through assets
vested by third parties to Council.
3. Diversion and discharges of stormwater from new impervious areas, as a result of greenfield development,
where these areas discharge to the stormwater network or through assets vested by third parties to Council
for on-going management.
The future adverse effects of diversions and discharges from the stormwater network will be managed by providing
for these activities to occur subject to meeting stormwater management requirements that ensure adverse effects
are appropriately minimised and mitigated in accordance with the NDC Outcomes.
Stormwater Management Planning
Stormwater management plans (SMPs) will continue to be a primary tool for larger greenfield and brownfield
development, to support the development and demonstrate how the performance requirements and NDC
Outcomes will be achieved, including applying an integrated stormwater management approach to achieve more
effective and multiple benefits.
SMPs will also be developed by Healthy Waters to support major stormwater network improvements to reduce
adverse effects and maximise benefits, or to establish sub-catchment requirements to address localised issues or
improve outcomes.
Where a SMP has been prepared and adopted for a specific development, area or sub-catchment, it will become
the ‘default’ management approach (implemented through the Stormwater Bylaw and other mechanisms). This
enables customised stormwater management requirements to be developed for specific areas to respond to the
nature of the site/receiving environment and future development and redevelopment.
Approval Processes
Healthy Waters will manage compliance with the NDC Outcomes and performance requirements through:
▪ Assessment of its own projects (and associated mitigation requirements), which will be available for
regulatory compliance auditing;
▪ Connection requirements, managed through approval processes under the Stormwater Bylaw; and/or
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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▪ Compliance with the Stormwater Code of Practice for new infrastructure that is to be vested in Council (also
managed through approval processes under the Stormwater Bylaw).
In this regard, the Stormwater Bylaw has an important role in ensuring that compliance with the conditions of the
Auckland Stormwater NDC is achieved. New vested infrastructure, or new/altered connections to the public
stormwater network are managed through conditions of approval that ensure that Council’s ability to comply with
its discharge consent is not compromised.
This is essential as the adverse effects associated with stormwater cannot effectively be managed ‘at the end of the
pipe’ alone – controls on inputs to the system are also required to achieve the NDC Outcomes and align with the
objectives and policies of the Auckland Unitary Plan and other statutory instruments.
Authorisation under the Auckland Stormwater NDC
In respect of future development and changes to, and development of, the stormwater network, these will be
authorised by the Auckland Stormwater NDC as follows:
▪ Where future stormwater networks or associated infrastructure will be incorporated into, or vested as part
of, Council’s stormwater network and the stormwater infrastructure and management requirements
(including those associated with an approved SMP) and Stormwater Code of Practice are met, this future
development will be authorised by the Auckland Stormwater NDC.
▪ Where a development cannot meet the stormwater infrastructure and management requirements, Healthy
Waters cannot ensure that the adverse effects are contained within the extent of adverse effects authorised
by the Auckland Stormwater NDC. Accordingly, the diversion and discharge of stormwater from such a
development is not authorised by the Auckland Stormwater NDC and a standalone stormwater discharge
consent will be required (in accordance with the relevant provisions of the Auckland Unitary Plan). It is
anticipated that under these circumstances, if a separate consent is granted by the Auckland Council’s
Consent Department, the assets associated with that consent will not be approved by Healthy Waters for
vesting in Council.
▪ Development/redevelopment that involves new (or altered) connections to the stormwater network will be
subject to the stormwater management requirements (including those associated with an approved SMP)
and relevant connection requirements under the Stormwater Bylaw.
▪ Projects that relate to renewals or improvements/extensions to stormwater infrastructure that change the
nature of stormwater flows will be authorised by the Auckland Stormwater NDC, subject to meeting the
stormwater infrastructure and management requirements noting that a key aspect of the NDC is to enable
the provision and development of infrastructure to support Auckland’s growth and development and
progressively reduce existing adverse effects.
The proposed connection/vesting requirements are provided in Attachment 2.
E.11 Assessing Progress Towards Outcomes - Six-year Targets
The NDC Outcomes are inherently ‘high level’ – being outcomes anticipated to occur at an overall, network wide
scale over time. To enable progress against the outcomes to be measured, targets for the first six years of the
resource consent are proposed and these are provided in Attachment 1. These targets include specific
performance measures and other actions to improve management of stormwater, including collaboration with
other parties. As indicated above, the targets have been the subject of consultation and refinement with key
stakeholders.
E.12 Monitoring and Review
E.12.1 Monitoring
Both Healthy Waters and the wider Auckland Council undertake a comprehensive range of monitoring to assess
resource pressures (ie growth and development), environmental response (including the state of the environment
and associated trends), and to gather information or address specific issues.
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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Environmental monitoring will be supported by stormwater network performance monitoring as established and
detailed in:
▪ Council’s Long Term Plan;
▪ Auckland Council’s Stormwater Asset Management Plan6; and
▪ The NDC Outcomes identified above.
Monitoring will be used to demonstrate progress against the NDC Outcomes and milestones and to assist in future
reviews of the Auckland Stormwater NDC.
E.12.2 Review Process
An important element of the Auckland Stormwater NDC is a review process to ensure that it remains relevant over
the lifetime of the resource consent. The management of a complex drainage network such as that in Auckland is
not static, but a process that evolves over time due to factors including:
▪ Changes in the statutory framework;
▪ Changes in community expectations and priorities;
▪ Improved understanding of network performance, issues and adverse effects and the effectiveness of
management responses;
▪ Technological advances.
As a result of this ongoing process of change and increased understanding, it is inevitable that the BPO for
managing the adverse effects of the network must also evolve and adapt to ensure that it remains relevant and
current in terms of delivering best practice and community and environmental outcomes.
To enable continuous improvement and adaptation to occur, a cyclical process of implementing the BPO while
undertaking monitoring, combined with regular six yearly review processes, is proposed. This will enable and
ensure that improved information and understanding is fed back to the consent review process to refine and
update the BPO and establish targets for the following six years. Where change is more significant, a formal
consent review may be required to update the Auckland Stormwater NDC as necessary. The process proposed for
implementation and review is shown in Figure 2.
As can be seen from this process, monitoring assessment and consultation are key elements to inform the review.
Where the implementation of the BPO continues to move towards the identified outcomes, and only minor
refinement is required, no statutory (RMA) review is required. However, when more fundamental or substantive
changes are necessary, a statutory review process under section 127 of the RMA will be undertaken by Healthy
Waters.
6 Current AMP is Stormwater Asset Management Plan 2015 – 2045, Version 1 – October 2015
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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Figure 2: Implementation, Monitoring and Review
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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E.13 Conditions of Consent
The Auckland Stormwater NDC will be subject to a comprehensive suite of conditions that include both general
requirements that apply over the entire network and in some instances catchment/sub-catchment specific
requirements. The latter will be adopted from existing consents where these conditions are enduring and are
required to ensure that specific outcomes or requirements of those consents, which were often determined
through significant community or court processes, are not lost or replaced by more general requirements.
Comprehensive conditions of consent are proposed in the application. These cover matters including:
1. Scope – defines the activities that are included in the consent and outcomes, targets and schedules that
form part of the consent conditions.
2. Operations and Maintenance Plan – requires a plan that incorporates a description of the processes in place
for, and key elements of, the operation and maintenance of the stormwater network, an asset register, an
inspection and maintenance programme, pre- and post- storm monitoring processes of critical or at risk
components of the network to minimise blockages and flood risk and identified levels of service.
3. Changes to Discharges/Land Development – specifies provisions and associated Schedules that detail
requirements for changes to stormwater infrastructure, vested stormwater infrastructure and connections
to the stormwater network.
4. Surrendering of existing consents – specifies a process for surrendering existing consents to ensure that
relevant conditions of existing consents are incorporated in the Auckland Stormwater NDC where they
impose specific requirements or obligations that are on-going and are not otherwise covered by the
Auckland Stormwater NDC.
5. Consent Holder Reporting and Review – specifies reporting requirements and frequency and a six-yearly
review process, as described in Figure 2 above, including consultation requirements and the process to
amend relevant Schedules and six-year targets in accordance with the outcomes of the review.
6. Manager Certification Process – specifies the matters that can be certified by the Auckland Council
Regulatory Manager.
7. Monitoring – specifies monitoring requirements, which are to be reported and used in the review processes.
8. Public Information – specifies the information and reporting that is to be made publicly available – including
flooding hazards, stormwater network, applicable Stormwater Management Plans, reporting and review
documentation and relevant standards/requirements;
9. Statutory Review – details the circumstances by which the resource consent can be reviewed, in accordance
with s128 of the RMA, including:
a. Where unanticipated and material adverse effects occur;
b. To amend conditions to reflect and changes in the statutory planning framework and its
implementation, including future requirements arising from Auckland Council’s implementation of
the NPSFM;
c. To take account of changes in objectives, methods and technology.
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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Attachment 1: NDC Objectives, Outcomes and Six-year Targets
ISSUE OBJECTIVES OUTCOMES SIX YEAR TARGETS (LTP and AMP performance standards will be updated
following reviews)
ISSUE 1: ASSETS
I1 The ability of the stormwater network to cost effectively meet the needs of current and future generations and achieve and maintain healthy receiving environments, is dependent on the design, quality, maintenance and renewal of built assets and their interaction with private networks and natural systems.
Safe Communities: Risk to our communities, including people, property and infrastructure is reduced - ensure that risk to people and property is managed to levels that have been established in consultation with the community, and reduce existing flood risk where it is above these levels.
Healthy and Connected Waterways: Stream, groundwater and coastal water values are maintained and enhanced and communities are connected with them - utilise streams, aquifers and harbours as integral natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on, and enhancing our community’s connection with, its waterways.
.
O1.1 Manage existing public stormwater assets to meet agreed levels of service.
O1.2 Manage erosion effects caused by discharges from the public stormwater infrastructure.
O1.3 Improve existing assets by taking the opportunities from redevelopment where they arise.
Council Stormwater Infrastructure Performance Standards (all DC)
a) Survey 95% of critical assets every 5 years (AMP)
b) Grade 4 critical assets will be repaired or renewed within 5 years (2015 -2045 AMP)
c) Grade 5 highly critical assets will be repaired or renewed within 24 months of identification (AMP)
d) Number of blockages in the stormwater network per 100km will be less than 20 per annum (AMP)
e) The number of complaints received about the performance of the stormwater network per 1000 properties connected to Auckland Council’s stormwater network will be less than 3 per 1000 (LTP)
f) Stormwater manholes that pop open in flood events are made safe within two hours: 100% (LTP)
Identified Reviews and Management Improvements for Managing the Council’s stormwater infrastructure (all DC)
g) Review vesting processes to ensure that assets from proposed development meet the requirements of AUP, NDC and Stormwater Code of Practice - measured by annual audit of a sample of vested assets. Process improvements as identified through the audit
h) Implement identified stormwater asset management improvement measures (ongoing BAU)
i) Complete asset and risk assessment of public coastal (completed) and stream outfalls (WA programme) - 2017/18 watercourse assessments completed (Figure 9.5)
j) Complete condition and risk assessments of large public stormwater dams (completed by 2023)
k) Ongoing review of criticality strategies and assessments for all asset types. Renewal strategy has been completed; critical flood risk asset monitoring strategy in place. Improvements implemented as identified (BAU)
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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ISSUE OBJECTIVES OUTCOMES SIX YEAR TARGETS (LTP and AMP performance standards will be updated following reviews)
l) Review complaints to identify potential issues and renewals (BAU, three yearly reporting of summary statistics from issues register)
Note: Progress reporting on AMP targets will be undertaken via the Stormwater AMP
Collaboration with Stakeholders
m) Regularly engage with other infrastructure providers on collaborative redevelopment opportunities (Co)
n) Implementation and review of the Stormwater Code of Practice and Bylaw (IC)
ISSUE 2: GROWTH
I2 The way the region grows and develops, and our ability to address existing adverse effects, will determine the quality and health of our freshwater and marine environment.
Support Growth: Growth through water sensitive development and provision of quality stormwater infrastructure is enabled - new and re-developed areas are supported by effective stormwater management and good quality infrastructure and development is undertaken in a way that meets the needs of our communities and maintains and enhances natural water systems.
O2.1 Align stormwater infrastructure planning and provision to development and intensification priorities.
O2.2 Integrate water sensitive design into new and major re-development. This can include promoting source control, at source treatment, bioretention, detention and attenuation, and protection and enhancement of streams.
O2.3 Enable effective land use and stormwater management planning and co-operation between developers and infrastructure providers.
O2.4 Establish clear standards and processes for the planning, development and vesting of good quality public stormwater infrastructure, particularly in terms of minimising operational and renewal costs, as well as minimising
Council Stormwater Infrastructure Performance Standards (all DC)
a) Input into stormwater management plans, including those prepared by developers, in response to all high priority growth areas during structure planning and consenting processes
b) 95% of formal enquires to stormwater development are responded to within 5 working days (AMP)
c) At least 95% of annual capital works programme to enable growth is delivered (AMP)
d) >$100,000 of other Council departments or CCOs growth projects are supported by the HW capital investment each year (AMP)
Identified Reviews and Management Improvements for Managing the Council’s public stormwater infrastructure
e) Provide updated guidance on the criteria for assets to be vested to Council and connections following approval of the NDC within one year of the granting of consent (DC)
f) Facilitate stream rehabilitation through identification of opportunities for offsetting through growth (initial list of offsetting projects completed, ongoing update as new opportunities arise) (IC)
Collaboration with Stakeholders
g) Assist in the implementation of stormwater management/land use requirements under the AUP, including advocating for water sensitive design in new growth / major intensification areas (IC)
h) Implementation and review of the Stormwater Code of Practice and Bylaw (IC)
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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ISSUE OBJECTIVES OUTCOMES SIX YEAR TARGETS (LTP and AMP performance standards will be updated following reviews)
community, environmental and cultural effects.
i) Assist in development and implementation of guidance on Water Sensitive Design; including Guideline GD04 (IC)
ISSUE 3: FLOODING
I3 A large number of buildings (residential and commercial) and critical infrastructure are at risk of flooding and the problem will increase if past land use and development practices continue.
Safe Communities: Risk to our communities, including people, property and infrastructure is reduced - ensure that risk to people and property is managed to levels that have been established in consultation with the community, and reduce existing flood risk where it is above these levels.
O3.1 Avoid the increase of existing flooding or creation of new flooding of habitable floors as a result of urban development and intensification.
O3.2 Reduce existing flood risk by taking the opportunities from redevelopment where they arise.
O3.3 Manage existing flood risk to meet levels of service agreed to keep people and property safe from significant harm from flooding, and minimise disruption to critical social and physical infrastructure connections across the city.
O3.4 Improved community understanding of, and resilience to, flood hazards.
Council Stormwater Infrastructure Performance Standard (all DC)
a) Council flood hazard GIS layer is maintained so that it is current and publicly available; reviewed on a two-yearly basis
b) The number of flooding events and the associated number of habitable floors affected: less than 1 per 1000 properties in Auckland per annum (LTP)
c) Proportion of habitable floors protected from flooding in a 1 in 10-year storm: > 99% (AMP)
d) Total habitable floors protected from flooding in a 1 in 100-year storm: > 97.5% (AMP)
e) Median response time to attend a flooding event, measured from the time that Auckland Council receives notification to the time that service personnel reach site: < 2 hours (LTP)
f) Major flood protection and control structures are maintained, repaired and renewed to a safe operating standard (AMP – mandatory national measure - however there are no such structures in Auckland)
Identified Reviews and Management Improvements for Managing the Council’s public stormwater infrastructure
g) Provide updated guidance on the criteria for assets to be vested to Council following approval of the NDC (as above, within one year of the granting of consent) (DC)
h) Flood resilience strategies are in place for habitable floors that are found to be unfeasible to protect from flooding within 10 years: >50% (IC) (AMP)
Collaboration with stakeholders-
i) Work with Civil Defence in identifying areas of flooding that pose a risk to life, as well as to critical infrastructure (Co)
j) Assist in the implementation of stormwater management/land use requirements under Unitary Plan, including protection of floodplains and overland flowpaths to prevent flooding from new development (IC)
k) Implementation and review of the Stormwater Code of Practice and Bylaw (IC)
AUCKLAND STORMWATER NDC – EXECUTIVE SUMMARY
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ISSUE OBJECTIVES OUTCOMES SIX YEAR TARGETS (LTP and AMP performance standards will be updated following reviews)
l) Assist in development and implementation of guidance on Water Sensitive Design, including Guideline GD04 (IC)
m) Regularly engage with Local Boards regarding local flooding issues (Co)
n) Regularly engage with other infrastructure providers on redevelopment opportunities and identification of critical infrastructure (Co)
ISSUE 4: STREAM HEALTH
I4 Urbanisation and poor stormwater management adversely affects Auckland’s urban streams and can cause a loss of aquatic habitat and biodiversity, resulting in biological degradation and impacts on ecological functioning of streams, on the community and on the mauri of freshwater and Maori customary uses of freshwater resources.
Healthy and Connected Waterways: Stream, groundwater and coastal water values are maintained and enhanced and communities are connected with them - utilise streams, aquifers and harbours as integral natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on, and enhancing our community’s connection with, its waterways.
O4.1 Maintain, operate and develop Council’s current and future public stormwater network to minimise and reduce adverse effects on streams, groundwater and coastal systems.
O4.2 Enhance urban streams and waterways by working collaboratively with key stakeholders such as mana whenua, Local Boards, community groups and the development community to take opportunities where they arise.
Council Stormwater Infrastructure Performance Standards
a) Number of fish passage barriers mitigated: average 10 per year (DC)
b) The ratio of the length of watercourse consented to be physically improved versus physically degraded in each year (kms Improved ÷ kms Degraded) 3 or more (LTP). (IC, Co, In)
Identified Reviews and Management Improvements for Managing the Council’s public stormwater infrastructure
c) Complete asset and risk assessment of public coastal (completed) and stream outfalls (WA programme) - 2017/18 watercourse assessments completed (Figure 9.5) (DC)
d) Complete a case study assessment of possible interventions on private streams, taking into account amongst other things ownership, liability and access issues within three years (DC)
e) Implement Healthy Waters’ Green Infrastructure Policy for Healthy Waters’ capital works projects (ongoing BAU) (DC)
f) Incorporate the Mauri model7 into Healthy Waters’ capital delivery project assessments - model developed, ongoing implementation for all significant projects (DC, Co)
g) Develop a region wide decision support system to prioritise interventions for contaminant management purposes (part of Council’s implementation of the NPSFM) and implement projects to improve water quality outcomes where opportunities are identified (completed by 2021) (DC)
Collaboration with stakeholders
7 The Mauri-model is a best practice tool that can be used to effectively measure and assess cultural impacts of stormwater operations and programmes as part of the project scoping, prioritisation and cost-benefit analysis process. See All Issues/Collaborative Outcomes below – this tool will be developed in conjunction with Mana Whenua
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ISSUE OBJECTIVES OUTCOMES SIX YEAR TARGETS (LTP and AMP performance standards will be updated following reviews)
h) Work with internal and external stakeholders to identify potential collaboration projects for the enhancement of streams (Co)
i) Facilitate stream rehabilitation through identification of opportunities for offsetting through growth (initial list of offsetting projects completed, ongoing update as new opportunities arise) (IC)
j) Assess feasibility of Council-wide database on stream information (Co)
k) Assist in the education and implementation of guidance on Water Sensitive Design; this includes protection of streams, provision of riparian buffers and protection of base flow and other stream enhancement measures (IC)
ISSUE 5: COASTAL HEALTH
I5 Stormwater contaminants, sourced from urban land use, stream erosion and transport activities, accumulate in low energy marine environments (such as estuaries and enclosed harbours) and in some areas, occur at levels that adversely affect marine life, community and Maori cultural values, and once diminished, affects Maori customary uses of coastal resources.
Healthy and Connected Waterways: Stream, groundwater and coastal water values are maintained and enhanced and communities are connected with them - utilise streams, aquifers and harbours as integral natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on, and enhancing our community’s connection with, its waterways.
As for O4.1 above
As for O4.2 above
Council Stormwater Infrastructure Performance Standards
a) Volume of contaminants removed from the stormwater network via Auckland Councils maintenance and renewal programmes: 5,000 tons per annum for catchpits (AMP) (DC)
b) Volume of contaminants removed from the stormwater network via Auckland Councils maintenance and renewal programmes: 10,000 tons per annum from de-silting ponds and wetlands (AMP) (DC)
Identified Reviews and Management Improvements for Managing the Council’s public stormwater infrastructure
c) Provide updated guidance on the criteria for assets to be vested to Council and connections following approval of the NDC within one year of the granting of consent (IC)
d) As for Stream Health:
Develop a region wide decision support system to prioritise interventions for contaminant management purposes (part of Council’s implementation of the NPSFM) and implement projects to improve water quality outcomes where opportunities are identified (completed by 2021) (DC)
Collaboration with stakeholders
e) Work with mana whenua and other parties to identify areas of safe consumption of kaimoana/mahinga kai and other aspects of coastal health and values (NPSFM –part of watershed implementation plans) (Co)
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ISSUE OBJECTIVES OUTCOMES SIX YEAR TARGETS (LTP and AMP performance standards will be updated following reviews)
f) Assist in the education and implementation of guidance on Water Sensitive Design; this includes provisions in respect of at-source reduction and on-site treatment and management of contaminant generating areas (IC)
ISSUE 6: GROUNDWATER
I6 Groundwater aquifers underlying urban areas can be adversely affected by land development and stormwater discharges to ground soakage.
Healthy and Connected Waterways: Stream, groundwater and coastal water values are maintained and enhanced and communities are connected with them - utilise streams, aquifers and harbours as integral natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on, and enhancing our community’s connection with, its waterways
As for O4.1 above
As for O4.2 above
Council Stormwater Infrastructure Performance Standards
a) As for Managing Effects on Coastal Health, focusing on managing contaminants to aquifers
Identified Reviews and Management Improvements for Managing the Council’s public stormwater infrastructure
b) As for Managing Effects on Coastal Health, focusing on managing contaminants to aquifers
c) Prepare guidance for soakage device design, including treatment requirements (TR2013/40 completed, ongoing implementation)
Collaboration with stakeholders
d) Assist in development and implementation of guidance on Water Sensitive Design; including recharge of high use aquifers, peat soils and stream baseflow (IC)
e) Input into the implementation and review of the Stormwater Code of Practice and Bylaw (IC)
ISSUE 7: EFFECTS ON WASTEWATER SYSTEM
I7 In parts of Auckland, particularly where there is a combined stormwater-wastewater network, flood waters are contaminated with wastewater which can cause a public health risk, especially in areas with high contact recreation, and affects the Mauri of the waterbody and thereby has an effect on social and Maori cultural values.
Healthy and Connected Waterways Stream, groundwater and coastal water values are maintained and enhanced and communities are connected with them - utilise streams, aquifers and harbours as integral natural components of Auckland’s stormwater system while reducing the adverse effects of stormwater runoff on, and enhancing our community’s connection with, its waterways
As for O4.2 above Collaboration with stakeholders (all Co)
a) Develop a strategy for investigation and management of identified issues relating to cross contamination
b) Collaborate with Watercare Services Ltd to identify the optimal solution to reduce overflows to the receiving environment for public and environmental health reasons for the central combined sewer area (Project CANOPy)
c) Regularly engage with Watercare Services Ltd and Building Control to identify and assess inflow and infiltration issues and collaboratively design and implement infrastructure upgrades
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ISSUE 8: COMMON TO ALL ISSUES
Collaborative Outcomes:
Stakeholders are engaged to achieve the best stormwater outcomes for present and future generations.
O8.1 Collaborate with Council departments and CCOs that have a key role in delivering positive stormwater outcomes.
O8.2 Build constructive, working relationships with key stakeholders to achieve integrated stormwater solutions and cost effective outcomes.
O8.3 Establish effective mechanisms for mana whenua to be appropriately engaged in stormwater management. This includes recognising and actively working to operationalise and integrate the relationship and cultural values mana whenua have with their waterways
O8.4 Work with the stormwater industry to continue to identify, refine and communicate best practice and increase industry capacity, resources and knowledge.
Council Stormwater Infrastructure Performance Standards (DC)
a) Proportion of mana whenua that are satisfied with Auckland Council’s engagement with iwi in relation to stormwater projects: 10/19 or more (LTP)
b) Percentage of projects that contribute to Maori outcomes: at least 95% (AMP)
c) >$100,000 of other Council departments or CCOs growth projects are supported by the HW capital investment each year (AMP)
d) Compliance with NDC – number of abatement notices, infringement notices, enforcement orders or successful prosecutions: 0 (zero) (AMP)
Identified Reviews and Management Improvements for Managing the Council’s public stormwater infrastructure
e) Take into account and be cognisant of current or future Iwi Management Plans (DC)
Collaboration with stakeholders (Co)
f) Develop and integrate, in partnership with mana whenua, best practice tools which can be used to effectively measure and assess cultural impacts of stormwater operations and programmes as part of the project scoping, prioritisation and cost-benefit analysis process (Mauri-model) - model developed, ongoing implementation for all significant projects
g) Establish a draft process to operationalise and integrate the relationship and cultural values mana whenua have with their waterways. This includes annual reporting on mana whenua engagement efficacy in order to determine when engagement took place in a project, what the value of the input was, and how mana whenua feedback was (or was not) incorporated
h) Regular engagement with iwi to assess implementation via the mana whenua hui
Prioritised Investment:
Benefits from limited resources are maximised by targeting our priorities to achieve the best outcomes we can afford
O8.5 Undertake regional prioritisation that targets investment in the right areas, as agreed within Council, with mana whenua and our community and in accordance with the Auckland Plan vision and statutory requirements.
O8.6 Establish levels of service that are relevant and affordable.
Efficient Business: O8.7 Undertake efficient and effective network operational,
Council Stormwater Infrastructure Performance Standards (DC)
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Robust systems, processes, practices and management are implemented to support delivery of stormwater services
renewals and maintenance programmes.
O8.8 Regionalise stormwater management through harmonisation of standards, contracts and business processes.
O8.9 Provide fit for purpose information systems and business tools.
O8.10 Undertake efficient and effective response to customers and incidents.
O8.11 Rationalise network consents and compliance requirements.
O8.12 Monitor and report performance.
As per AMP targets above.
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Attachment 2: Auckland Stormwater NDC Works, Connections and Vesting Performance Requirements
Council renewal, maintenance and upgrade works8
1. No new/additional habitable floor affected by flooding in 1% AEP event
2. No adverse effect on operation and structural integrity of other infrastructure in 1% AEP event
3. No increase in inundation that affects a building on property in 10% AEP
4. No loss in overland flow path capacity, unless provided by other means
5. All major capital works projects consider, and where appropriate implement, a green infrastructure option in accordance with the Healthy Waters Green Infrastructure Policy
6. Significant erosion at a (pubic stormwater) outfall, which is the result of the operation of that outfall, is remedied/stabilised
7. Appropriate erosion protection/mitigation is provided for any new outfall in accordance with the Stormwater Code of Practice
8. Where stormwater is directed to a different receiving environment then the change in discharge either:
- Does not decrease water quality in the receiving environment; or
- Is treated by a water quality device designed in accordance with GD01/TP 10
Where any of the above performance requirements cannot be achieved, alternative levels of performance are to be established as the BPO in a Stormwater Management Plan that is
certified by the Manager, Auckland Council Regulatory Services or delegate
Connection/Vesting Requirements – Private Development
Issue/Receiving Environment Brownfields small Brownfields large – 20 lots or over new/re-
developed 5,000m2 impervious surface
Greenfield
Catchments/areas
Within area covered by certified CMP9/SMP
▪ Stormwater management or connection requirements in accordance with the CMP/SMP
Note that where specifically addressed in a CMP/SMP these requirements supersede any performance requirements below
In other areas ▪ Requirements below are met; or ▪ Where requirements cannot be met, a SMP
that includes supporting information that demonstrates the best practicable option has been adopted
A SMP detailing:
▪ The management approach/ key elements including:
- Areas of development, including roads and reserves
- Location of vested infrastructure, including green infrastructure
- Areas of on-site and communal (public) stormwater management
- The protection of significant site features and hydrology
- How the connection/vesting requirements below are met or the alternative that is proposed
▪ How an Integrated Stormwater Management Approach has been adopted in the design and associated stormwater management in accordance with AUP Policy E1.3.10 to:
8 Note: These projects do not create impervious area, but rather affect how stormwater is conveyed and discharged. Development that creates impervious area is covered by the vesting/connection requirements for brownfield and greenfield development. 9 CMP – Catchment Management Plan (where one has been prepared and certified)
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- Minimise the stormwater related effects of development
- Retain/restore natural hydrology as far as practicable
- Minimise the generation and discharge of contaminants and stormwater flows at source
- Minimise the generation and discharge of gross stormwater pollutants
- Minimise temperature related effects
- Enhance freshwater systems including streams and riparian margins
- Minimise the location of engineered structures in streams
Water Quality (note: these apply in addition to any land use/consent requirements)
Degraded or sensitive aquatic
environment:
▪ Stream ▪ Coastal Degraded 1 or 2 ▪ Quality sensitive
groundwater aquifer (see AUP)
▪ No more than 25 m2 of non-inert building material10 unless treated by a water quality device designed in accordance with GD01/TP 10 for the contaminant concerned
▪ Gross pollutant traps designed in accordance with GD01/TP 10 for commercial/industrial waste storage/handling or loading/unloading areas treatment and communal waste storage areas for apartments and multi-unit developments
▪ Treatment of all impervious areas by a water quality device designed in accordance with GD01/TP 10 for the relevant contaminants
Or
▪ An alternative level of mitigation determined through a SMP that:
- applies an Integrated Stormwater Management Approach (as per above);
- meets the NDC Outcomes;
- is the BPO
▪ Gross pollutant traps designed in accordance with GD01/TP 10 for runoff from:
- Commercial/industrial waste storage/handling or loading/unloading areas treatment
- Communal waste storage areas in apartments and multi-unit developments Other receiving environments ▪ Gross pollutant traps designed in accordance with GD01/TP 10 for commercial/industrial waste storage/handling or loading/unloading areas treatment and communal waste storage areas for apartments and multi-unit developments
Stream Hydrology
Within a SMAF ▪ No additional requirements to those of AUP
Where discharge is to a
stream via public stormwater
network outside of SMAF
▪ No additional requirement to MIA controls in AUP
▪ Detention of the 95th %ile event with a drain-down period of 24 hours
Or
▪ An alternative level of mitigation determined through a SMP that:
- applies an Integrated Stormwater Management Approach (as per above);
- meets the NDC Outcomes;
▪ Achieve equivalent hydrology (infiltration, runoff volume, peak flow) to pre-development (grassed state) levels;
Or
▪ Provide retention (volume reduction) of a minimum of 5mm runoff depth for all impervious areas; and
10 Non-inert building material include: unpainted galvanised iron and unpainted copper roofing and cladding
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- is the BPO
Note that in establishing alternative mitigation requirements in existing urban areas, regard can be had to the nature of the downstream environment, including whether the stream is lined or significantly modified such that hydrological mitigation
▪ Provide detention (temporary storage) with a draindown period of 24 hours for the difference between the pre-development (grassed state) and post-development runoff volumes from the 95th percentile, 24 hour rainfall event minus the retention volume for all impervious areas.
Or
▪ An alternative level of mitigation determined through a SMP that:
- applies an Integrated Stormwater Management Approach (as per above);
- meets the NDC Outcomes;
- is the BPO
Flooding
Property/pipe capacity:
10% AEP event
▪ Assess pipe capacity for MPD of contributing catchment to first manhole and (if required):
- upgrade the pipe to the first manhole
- provide attenuation of 10% flow to that
immediately prior to development
▪ Develop/upgrade pipe network of the development to Stormwater Code of Practice requirements
▪ Assess capacity of downstream pipe network11 for MPD of contributing catchment and (if required):
- upgrade the downstream pipes to the discharge point; or
- provide attenuation of 10% flow to that immediately prior to development
Or ▪ Demonstrate through a SMP how flows will be managed to avoid flooding of other property
Buildings – 1% AEP event ▪ No additional requirement to MIA controls in AUP
▪ Manage/mitigate 10% and 1% AEP peak flow to that immediately preceding development Or
▪ An alternative level of mitigation determined through a SMP that:
- applies an Integrated Stormwater Management Approach (as per above);
- meets the NDC Outcomes;
- is the BPO
▪ Develop to Stormwater Code of Practice ▪ Develop in accordance with SMP as above
Assets
General ▪ All new assets to be vested in Council are to be built in accordance with the Stormwater Code of Practice
11 Note, this is not required where there is no downstream network
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Connection Requirements – AT/NZTA Transport Projects12
Issue/Receiving Environment Small projects – up to
1,000 m2 of new
impervious area
Off-road walking and
cycling, ferry
infrastructure etc. New
impervious area
greater than 1,000m2
of new impervious
area
Development of new / redevelopment of
impervious area for:
- existing high use roads that includes new area
greater than 1,000m2
- other roads that includes new area greater than
5,000m2
Development/redevelopment of high use
carpark (new/redeveloped area greater than
1,000m2)
Catchments/areas
Within area covered by certified CMP/SMP
▪ Stormwater management or connection requirements in accordance with the CMP/SMP
Note that where specifically addressed in a CMP/SMP these requirements supersede any performance requirements below
In other areas ▪ General performance requirements
- No new/additional habitable floor affected by flooding in 1% AEP event
- No adverse effect on operation and structural integrity of other infrastructure in 1% AEP event
- No increase in inundation that affects a building on property in 10% AEP
- No loss in overland flow path capacity, unless provided by other means
Where these requirements cannot be met, a SMP that includes supporting information to justify an alternative as the BPO is required. Where the existing road corridor is constrained off-setting within the same catchment may form a part of the mitigation approach.
Water Quality (note: these apply in addition to general performance requirements)
All receiving environments
▪ No requirements ▪ Treatment of new road area and any existing road area directed to same point by a water quality device designed in accordance with GD01/TP 10 for the relevant contaminants
Or
▪ Treatment of equivalent area of high use road within same catchment by a water quality device designed in accordance with GD01/TP 10 for the relevant contaminants
Or
▪ An alternative level of mitigation determined through a SMP that:
- applies an Integrated Stormwater Management Approach (as per above);
- meets the NDC Outcomes;
▪ Treatment of new/redeveloped area (or all carpark area where it is >50% of the site) by a water quality device designed in accordance with GD01/TP 10 for the relevant contaminants
Or
▪ Treatment of equivalent area within same catchment by a water quality device designed in accordance with GD01/TP 10 for the relevant contaminants
Or
▪ An alternative level of mitigation determined through a SMP that:
- applies an Integrated Stormwater Management Approach (as per above);
- meets the NDC Outcomes;
12 Note that roads developed as part of greenfield/brownfield development are considered as part of that development
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- is the BPO - is the BPO
Stream Hydrology
Within a SMAF ▪ No additional requirements to those of the AUP and general requirements above
Where discharge is to a
stream via public stormwater
network outside of SMAF
▪ No additional requirements
Flooding
Property/pipe capacity:
10% AEP event
Projects – up to 5,000 m2 new impervious area
▪ Assess pipe capacity for MPD of contributing catchment to first manhole and (if required):
- upgrade the pipe to the first manhole to Stormwater Code of Practice requirements
or
- provide attenuation of 10% flow to that immediately prior to development
Projects – 5,000 m2 or more of new impervious area13
▪ Assess capacity of downstream pipe network14 for MPD of contributing catchment and (if required):
- upgrade the downstream pipes to the discharge point; or
- provide attenuation of 10% flow to that immediately prior to development
or
▪ Demonstrate through a SMP how flows will be managed to avoid flooding of other property
Buildings – 1% AEP event ▪ No new/additional habitable floor flooding in the 1% AEP event.
Assets
General ▪ All new stormwater assets to be operated by Healthy Waters are to be built in accordance with the Stormwater Code of Practice
13 It is anticipated that capacity and other issues will be assess in conjunction with Healthy Waters 14 Note, this is not required where there is no downfield network